A3.238: Communities of Cladocora Caespitosa Beds and Reefbanks of Moderately Exposed Or Semi-Exposed Infralittoral Rock

European Red List of Habitats - Marine: Mediterranean Sea Habitat Group

A3.238: Communities of Cladocora caespitosa beds and reefbanks of moderately exposed or semi-exposed infralittoral rock

Summary This habitat is only found in the Mediterranean Sea where the dominant species Cladocora caespitosa is broadly distributed. The habitat however, is developed on specific sites where it forms extensive beds and banks, particularly Mjlet National Park (Croatia, Adriatic Sea), Kotor Bay in Montenegro and in the Columbretes Islands Marine Reserve (Spain, NW Mediterranean). Severe declines have been reported from these sites where they have been impacted by a range of threats among them increasing seawater temperatures, eutrophication, coastal works and colonization of invasive algal species.Within these protected areas damage to the colonies by threats such as anchoring, fishing, recreational diving, dredging activities, should be controlled. Establishing a long-term monitoring program to follow its conservation status, particularly in the actual context of global change impacts should also be prioritised. Synthesis This is an scattered habitat mostly formed by an endemic dominant structural species, Cladocora caespitosa, with an area that does not seem to exceed more than 0,5km2 and its presence in less than 34, 10 x 10km grid squares.The habitat is distributed in at least 10 localities where it forms large beds or reef banks. A continuous decline in habitat abundance has been observed in most sites, ranging between 19- 80% over different periods at different sites. Long term monitoring has only been undertaken at one bank, and here there have been declines of up to 80% in the last 20 years. This has been attributed to an increase in dseawater temperature. Because of itsrestricted geographical distribution and the continuing decline observed in its spatial extent, this habitat has been assessed as Endangered for both EU 28 and EU 28+.

Overall Category & Criteria EU 28 EU 28+ Red List Category Red List Criteria Red List Category Red List Criteria Endangered A2a, A2b Endangered A2a, A2b

Sub-habitat types that may require further examination None. Habitat Type Code and name A3.238: Communities of Cladocora caespitosa beds and reefbanks of moderately exposed or semi-exposed infralittoral rock

1 Large banks of Cladocora caespitosa in Mljet National Park, Croatia (© P. Krucic). Reef of Cladocora caespitosa (Illa Grossa, Columbretes, Spain (© D.K. Kersting).

Habitat description The habitat formed by the zooxanthellate coral Cladocora caespitosa occurs on a wide range of substratum, a range of depths (commonly from 5 to 40 m depth), and hydrodynamic conditions. The colonies of this species, both dead and alive, provide a persistent biogenic structure or bioconstruction. Erect macroalgae can grow interspersed with the colonies or even overgrowing them.

Indicators of quality:

The status of habitat can be estimated based on the growth rates of the colonies of C.caespitosa, the cumulative cover area and population trends as well as rate of necrosis observed. Other indicators of quality of the habitat are macroalgal cover, including exotic species cover.

Characteristic species:

Rhodophyta (red algae)- Amphiroa rigida, Laurencia obtusa, Haliptilon virgatum, Lithophyllum incrustans, Neogoniolithon brassica-florida, Peyssonnelia squamaria.

Phaeophyta- Dictyopteris polypodioides, Padina pavonica, Cystoseira sauvageauana, Dictyota dichotoma v. intricata, Zanardinia typus.

Chlorophyta (green algae)- Anadyomene stellata, Acetabularia acetabulum, Caulerpa cylindracea, Halimeda tuna.

Cnidaria- Cladocora caespitosa Classification This habitat may be equivalent to, or broader than, or narrower than the habitats or ecosystems in the following typologies.

EUNIS (v1405):

Level 5 of the EUNIS classification. A sub-habitat of A3.2 Mediterranean moderatel energy infralittoral rock.

2 Annex 1:

1170 Reefs

MAES:

Marine - Marine inlets and transitional waters

Marine – Coastal

MSFD:

Shallow sublittoral rock and biogenic reef

EUSeaMap:

Shallow photic rock or biogenic reef

IUCN:

9.7 Macroalgal/kelp Does the habitat type present an outstanding example of typical characteristics of one or more biogeographic regions? Yes Regions Mediterranean Justification The community formed by the dominant species Cladocora caespitosa is found only in the Mediterranean Sea. Here, the species is widespread and can be locally abundant, however, only a particular equilibrium between hydrodynamic protection and high water exchange through strong currents seems to allow the development of extensive C. caespitosa habitats in few locations in the Mediterranean. Geographic occurrence and trends

Recent trend in Recent trend in Current area Region Present or Presence Uncertain quantity (last 50 quality (last 50 of habitat yrs) yrs) Adriatic Sea: Present Aegian-Levantine Sea: Present

Ionian Sea and the Central 2 Mediterranean Sea 0.5 Km Decreasing Decreasing Mediterranean Sea: Present Western Mediterranean Sea: Present

Extent of Occurrence, Area of Occupancy and habitat area Extent of Occurrence (EOO) Area of Occupancy (AOO) Current estimated Total Area Comment EU 28 76,605 Km2 32 0.5 Km2 EU 28+ 1,062,166 Km2 34 0.5 Km2

3 Distribution map

This map has been generated using data from IUCN and supplemented with expert opinion. EOO and AOO have been calculated on the available data presented in this map however these should be treated with caution as expert opinion is that this may not indicate the full distribution of the habitat.

How much of the current distribution of the habitat type lies within the EU 28? Cladocora caespitosa reefs and beds have been found mostly in EU 28 countries (Cyprus, Spain, Croatia, and Italy) and also in the EU 28+ in Montenegro. Its current estimated area is approx. 0.5km2 based on total area of bank or accumulated colony area.

Trends in quantity There are very few cases where Cladocora caespitosa habitats have been described in terms of the cover, distribution, health status and population dynamics of the main dominant species and its communities. From this information, it can be inferred that there has been a general decrease of the quantity of the habitat as its key species cover is reduced. In Spain, habitat loss of between 55 % and 80 % due to recurrent mortalities has been observed over last 10 years. Similarly, in the Adriatic more than 90% of Cladocora caespitosa colonies from the bank near Iz Island died during 2001-2005 and recurrent mortalities has also been observed last years in the Mljet banks. Climate change acting with other pressures is considered to be the main caused the reduction of the habitat by more than 50% in areas such as Gulf of La Spezia (northern Tyrrhenian Sea).

● Average current trend in quantity (extent) EU 28: Decreasing EU 28+: Decreasing ● Does the habitat type have a small natural range following regression? No

4 Justification The habitat is very restricted in size but large banks occur in the western basin and the Adriatic Sea and the EOO exceeds 50,000km2. ● Does the habitat have a small natural range by reason of its intrinsically restricted area? No Justification Cladocora caespitosa reefs and large beds are known only from very few locations, however the structural main species is widely distributed in the Mediterranean. Trends in quality A decrease of the habitat quality constituted mainly by Cladocora caespitosa banks and beds has been widely observed. Bleaching, necrosis, change on species composition because of invasive species colonization has been reported in Italy, Spain and Croatia. It has been observed that infralitoral photophilic algal communities changed to communities with a high presence of invasive alga species.

● Average current trend in quality EU 28: Decreasing EU 28+: Decreasing Pressures and threats

Illegal trawling and dredging are probably the most destructive impacts currently affecting the communities formed with the coral Cladocora caespitosa. Mass mortalities related to seawater warming and summer heat waves have also been reported in several Mediterranean sites and will increase with climate change. Negative impacts resulting from eutrophication (N, P and organic matter) and industrial and sewage discharges have also been reported affecting the community composition such as increasing the macroalgae cover. Sub-lethal effects from exotic algal invasion can also affect the growth of colonies and therefore the communities within it.

List of pressures and threats Biological resource use other than agriculture & forestry Intensive fish farming, intensification Benthic or demersal trawling Benthic dredging Pollution Nutrient enrichment (N, P, organic matter) Toxic chemical discharge from material dumped at sea Invasive, other problematic species and genes Invasive non-native species Natural biotic and abiotic processes (without catastrophes) Accumulation of organic material Climate change Temperature changes (e.g. rise of temperature & extremes)

Conservation and management

The communities of Cladocora caespitosa are present within protected areas in the Mediterranean, such as

5 the Columbretes Islands and Mljet Islands and the species is known to occur in other protected sites. Additional conservation actions to protect and manage this habitat should include: extending the current knowledge on the distribution and community composition and trends of this habitat, especially at known localities where the information is lacking and to ensure the protection of the main and larger communities of C. caespitosa identified to date. At these locations, damage to the colonies by threats such as anchoring, fishing, recreational diving, dredging activities, should be controlled. Establishing a long-term monitoring program to follow its conservation status, particularly in the actual context of global change impacts should also be prioritised.

List of conservation and management needs Measures related to wetland, freshwater and coastal habitats Restoring/Improving water quality Measures related to marine habitats Other marine-related measures Restoring marine habitats Measures related to spatial planning Establish protected areas/sites Legal protection of habitats and species Measures related to hunting, taking and fishing and species management Regulation/Management of fishery in marine and brackish systems Conservation status Annex 1:

1170: MMED XX.

Cladocora caespitosa appears in the Annex 2 of the Barcelona Convention. Large beds and colonies forming reefs could be considered to be included in the Annex 1 of Habitats Directive (Directive 92/43/CEE) under Habitat 1170 “Reefs” and listed on CITES Appendix II.

The species is listed as Endagered by IUCN Red list (2015).

When severely damaged, does the habitat retain the capacity to recover its typical character and functionality? The populations of the dominant species of this habitat can recover from the mortality events through recruitment of new individuals to existing colonies and the establishment of new colonies, however the recruitment rate for this long-lived species is extremely low and not able to compensate for the increasing mortality rates. It has an estimated generation time of 30 years.

Effort required 50+ years Naturally

Red List Assessment

6 Criterion A: Reduction in quantity Criterion A A1 A2a A2b A3 EU 28 35 % >50 % >50 % unknown % EU 28+ 35 % >50 % >50 % unknown %

There is limited long term monitoring data of this habitat except from one location where a reduction in the banks of between 50-80% has been observed. At other sites, the information is fragmented but shows declines in quantity of between 14% to 90%. Expert opinion is that losses in recent years have been around 35%. Based on these observations and that its main pressure, increase seawater temperature, will continue over the next 50 years, it is inferred an intermediate decline affecting more than 50% of the habitat. The habitat has therefore been assessed as Vulnerable under Criterion A1 for both the EU 28 and EU 28+ and as Endangered under criteria A2a A2b. It is Data Deficient for A3.

Criterion B: Restricted geographic distribution B1 B2 Criterion B B3 EOO a b c AOO a b c EU 28 >50,000 Km2 Yes Yes 10 32 Yes Yes 10 no EU 28+ >50,000 Km2 Yes Yes 10 34 Yes Yes 10 no

Reefs and large beds are known only from 10 locations, and the AOO is less than 50. This habitat has shown a continuing decline in its spatial extent in the last 50 years and this trend is expected to continue as seawater temperatures rise.

This habitat has therefore been assessed as Least Concern under B1 and B3 and Vulnerable under Criterion B2 (a,b,c) for the EU 28 and EU 28+.

Criterion C and D: Reduction in abiotic and/or biotic quality C/D1 C/D2 C/D3 Criteria Extent Relative Extent Extent Relative C/D Relative severity affected severity affected affected severity EU 28 unknown % unknown % 50 % intermediate % unknown % unknown % EU 28+ unknown % unknown % 50 % intermediate % unknown % unknown %

C1 C2 C3 Criterion C Extent Relative Extent Extent Relative Relative severity affected severity affected affected severity EU 28 unknown % unknown % 50 % intermediate % unknown % unknown % EU 28+ unknown % unknown % 50 % intermediate % unknown % unknown %

D1 D2 D3 Criterion D Extent Relative Extent Relative Extent Relative affected severity affected severity affected severity EU 28 unknown % unknown% unknown % unknown% unknown % unknown% EU 28+ unknown % unknown% unknown % unknown% unknown % unknown%

The colonization of algae invasive species such as Womerslella setacea,Caulerpa cylindracea and Lophocladia lamellandi has been reported in severals of the largest reef banks known (Montenegro, Croatia and Spain) although there are not estimations on the percentage of change in community composition by these species. In Montenegro, recent studies also mentioned a large

7 proportion of the reefs banks found dead and there are some informal reports of historical regressions from the coastal areas.

Based on a decrease on the abiotic quality (seawater temperature) that is affecting all colonies, it is infered that there has been an intermediate decline affecting more than 50% of the populations from the past 20 years to the future. Based on this substantial reduction, the habitat type is assessed as Vulnerable under Criterion C2 and C/D2.

Criterion E: Quantitative analysis to evaluate risk of habitat collapse Criterion E Probability of collapse EU 28 unknown EU 28+ unknown

There is no quantitative analysis available to estimate the probability of collapse of this habitat type. Therefore, the habitat type is assessed as Data Deficient under Criterion E.

Overall assessment "Balance sheet" for EU 28 and EU 28+ A1 A2a A2b A3 B1 B2 B3 C/D1 C/D2 C/D3 C1 C2 C3 D1 D2 D3 E EU28 VU EN EN DD LC VU LC DD VU DD DD VU DD DD DD DD DD EU28+ VU EN EN DD LC VU LC DD VU DD DD VU DD DD DD DD DD

Overall Category & Criteria EU 28 EU 28+ Red List Category Red List Criteria Red List Category Red List Criteria Endangered A2a, A2b Endangered A2a, A2b

Confidence in the assessment Medium (evenly split between quantitative data/literature and uncertain data sources and assured expert knowledge) Assessors D. Kersting, & M. del Mar Otero.

Contributors P. Kruzic, R. Metalpa, C. Cerrano, C. Linares, V. Mačić, E. Ballesteros.

Reviewers C. Numa & L. Tunesi. Date of assessment 13/10/2015 Date of review 07/01/2016

8 References

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